A magnetic tunnel junction (MTJ) device includes two ferromagnetic layers separated by a thin insulator. A relative magnetization direction of each of the ferromagnetic layers determines a state of an MTJ. An MTJ typically includes two states of resistance, a low resistance state and a high resistance state. An MTJ is in a high resistance state when both of the ferromagnetic electrodes of the MTJ are magnetized in the same direction. An MTJ is in a low resistance state when the ferromagnetic layers are magnetized in opposite directions. Relative magnetization directions of an MTJ device may be changed by an applied external magnetic field.
MTJ devices may find application in magnetic storage devices. For example, MTJ devices find application in read-heads of hard disk drives in which the magnetic state of the hard disk platter may be determined based on the resistance of an MTJ read head flying over the platter. MTJ devices may also find application in magnetoresistive random access memory in which data may be stored in and read from MTJ devices.